i don't think they are, they already have the Corvette ZR1 which would outdue a Stingray or be about the same so i don't think there's any need for a Stingray, that was just a concept which personally i didn't like how it looked except for the split rear window, rims and the way it looked on the sides, the front and rear looked ugly to me, but from what i hear GM would be to focused on coming out with the Camaro Z28 in 2011, its supposed to be a beast, it would easily out perform the new Mustang Shelby GT500 and i'd assume it would be cheaper to, the Z28 will have the supercharged LSA which is a detuned supercharged LS9, the LS9 is in the C6 Corvette ZR1, the LSA is out of a Cadillac CTS-V, the Z28 Camaro will have 556 HP and 551 ft lbs of TQ, so like i say with GM having out a Corvette Z06 and Corvette ZR1 and also rumored of putting a LSA (detuned LS9 from Corvette ZR1) in the new Camaro for the Z28 if it goes thtough then they're not going to focus on a new Corvette Stingray
http://www.autotropolis.com/auto-industry-news/chevy-camaro-adding-convertible-z28-models-for-2011.html